The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Vehicles include an engine system that produces drive torque to drive wheels of the vehicle. Typically, the engine system includes an internal combustion engine. Internal combustion engines produce drive torque by combusting a mixture of air and fuel in cylinders. Combustion within the cylinders drives pistons that rotate a crankshaft and thereby produce the drive torque. Combustion of the air-fuel mixture produces exhaust that is expelled from the cylinders.
Control systems have been developed to control the drive torque produced by internal combustion engines. Stop-start engine control systems have been developed to increase fuel economy and reduce emissions. Stop-start systems selectively shut down and subsequently restart the engine during periods of vehicle operation when drive torque from the engine is not required.
For example, stop-start systems may shut down the engine as the vehicle slows to a stop when approaching a stop light. The stop-start systems may restart the engine when a driver of the vehicle releases a brake pedal and depresses an accelerator pedal, indicating vehicle acceleration is desired. The driver may release the brake pedal and depress the accelerator pedal after the vehicle comes to a stop and the stop light changes. Alternately, the driver may release the brake pedal and depress the accelerator before the vehicle comes to a stop in what may be referred to as a change of mind event. Accordingly, stop-start systems may periodically shut down and restart the engine during vehicle operation based on inputs from the driver and/or various operating conditions, such as vehicle speed and engine speed.